LONDON — Juan Martin del Potro squeaked into the semifinals of the ATP World Tour Finals by beating Roger Federer 6-2, 6-7 (5), 6-3 on Thursday — the slimmest possible margin to advance and knock Andy Murray out of the tournament.

The result means del Potro and Federer both advance after a three- way tie in Group A, with Murray’s elimination coming down to the last game after three rounds of group matches.

All three players finished the round-robin stage with two wins and identical 5-4 set records, but Murray had the lowest percentage of games won. Had del Potro lost just one more game against Federer, Murray would have advanced at the Argentine’s expense.

In Group B, Robin Soderling has already clinched a semifinal spot, while Nikolay Davydenko and Novak Djokovic are still in contention ahead of today’s matches. Rafael Nadal was eliminated after two straight losses.

Yankees’ voice signing off

NEW YORK — Bob Sheppard has no intentions of returning to his longtime job as the public-address announcer at Yankee Stadium, MLB.com reported.

Sheppard, who is 99, hasn’t worked a game since late in the 2007 season because of illness.

“I have no plans of coming back,” Sheppard said. “Time has passed me by, I think. I had a good run for it. I enjoyed doing what I did. I don’t think, at my age, I’m going to suddenly regain the stamina that is really needed if you do the job and do it well.”

Sheppard added he doubts “very, very much” that he’ll be able to resume his duties for even one game next season.

“It’s not just the two hours or three hours of baseball,” he said. “It’s the trip, the preparation, the trip home, and a long, long day. I think at my age, it’s time to accept the fact that I had a great run. A great run. And I only made a few mistakes along the way.”

• The Toronto Blue Jays signed shortstop Alex Gonzalez to a one-year deal worth $2.75 million that includes a club option for 2011. He split last season between Cincinnati and Boston, batting .238 with eight home runs and 41 RBIs.

McIlroy, McDowell take lead

SHENZHEN, China — Rory McIlroy and Graeme McDowell shot a better-ball 58 to give Ireland a three-stroke lead over Argentina after the first round of the World Cup of Golf.

Argentina’s Tano Goya and Rafael Echenique were at 11-under 61, with Japan another shot behind. The United States duo of Nick Watney and John Merrick was tied for 15th at 5-under 67 after four birdies by Watney.

Today’s second round will be alternate-shot, as will Sunday, while Saturday will be better-ball again.

Pike slated to start for Bearcats

CINCINNATI — Senior quarterback Tony Pike, who has been nursing a sore left forearm, is expected to run Cincinnati’s offense tonight, when the Bearcats play their final home game against Illinois.

• Left tackle Jason Fox is sick and listed as doubtful for Miami’s game Saturday at South Florida.

More in Sports

“This is one of the great jobs in all of sports,” Colorado AD RIck George said Sunday. “There's not a better job in America than here in Colorado." Translation: If you’re not here to win championships, pal, don’t join the party.

If recent history is any indication, Helton likely faces an uphill climb to become the first Colorado player inducted into Cooperstown because of the bias that voters tend to hold against hitters who spent their careers playing home games at elevation.

The inspiration for the nickname came from "the outdoors, the sunshine, that feeling you get when you live here in Colorado," Vibes general manager Chris Phillips explained during Monday's name unveiling.

In his long-running role as the Chargers’ yappy quarterback, Rivers is the football villain Denver loves to hate most. On this November afternoon, Rivers inexplicably decided to pick a fight with Harris, the Broncos’ shutdown corner.